I have 4 in my garage. One is mounted on the wall, and three are on the floor for me to trip over, all of which are right next to the little sensor for the garage door. I also have 2 in the kitchen on the counter, but don't have any elsewhere in the house. I also have one of those small disposable ones in each of the Hot Rods. The black pointy thing next to the extinguisher is my anvil, so I can trip over it also.